I track my balance and stake rewards quite carefully, is it possible that I receive stakes which fully confirm yet don't add to my balance?

I added a specific amount to my wallet (say, 100,000) to keep track of stake rewards. So if my balance is at 114,328, I have it recorded in my spreadsheet that I purchased 100,000 and got 14,000 for free. Then I see a notification [stake: 1584.384595], it gets 128 confirmations and a check mark, but my balance stays at 114,328. This doesn't happen all the time, but I've noticed it two or three times now so I don't think I'm just crazy.